1. Field of the Invention
The invention relates to a method and apparatus for sterilizing refuse, in particular hospital refuse, using a plurality of disposable refuse containers which after loading with refuse are hermetically sealed by a cover and then introduced preferably severally into a sterilization tunnel and thereafter irradiated with microwaves, water or a disinfectant being introduced into the refuse of the refuse containers either before or during the microwave irradiation and the refuse container or containers then being discharged at a discharge end from the sterilization tunnel.
2. Description of the Prior Art
De-OS 3,317,300 discloses a container for receiving infected refuse, in particular hospital waste. To prevent infections said refuse is sterilized with the aid of microwaves, this being possible because the externally sealable container consists of a material through which microwaves can pass. Said container is equipped in its interior with an insertable and sealable disposable inner container for the infected refuse which consists of a substantially moisture-tight nontearable material which however allows steam and/or microwaves to pass. The outer container of this arrangement can be constructed as pressurized container.
At the inner side of the cover of said inner container a bag or the like containing liquid, preferably disinfectant, may be attached. During the microwave treatment the liquid in the interior of the bag is heated, partially vaporizes and thereby finally causes the bag to burst, the content thereof being emptied into the surrounding refuse.
EP 0 049 430 discloses a bulk material container having a cover, preferably for use as disposable transport vessel, which can also be used for receiving hospital waste.
DE-OS 2,908,086 discloses a method for disinfecting and sterilizing articles infected with germs, said method residing in that in the space surrounding the article to be treated a disinfectant is atomized. This known method can furthermore be developed in that the article surrounded by the disinfectant is irradiated with microwaves. The disinfection operation is carried out in a closed and sealed disinfection chamber, an atomizing or nebulizing device for disinfectant being arranged within the disinfection chamber. A further development of this disinfection chamber resides in that in the latter a microwave device is provided and outside the disinfection chamber a control device with which firstly the atomizing device is switched on and then, after formation of a disinfection mist in the disinfection chamber, the microwave device is switched on.
In such a disinfection chamber, which may also be constructed in the form of a sterilization tunnel, a plurality of microwave generators being arranged at the walls of the tunnel in succession, there is however the possibility on introduction of the refuse directly into the chamber of germs escaping from said chamber or tunnel, for example on formation of a draught, i.e. the germs or bacteria to be killed may by chance not be kept sufficiently long in the chamber or in the tunnel and consequently a 100% sterilization and disinfection cannot be achieved with high certainty.
DE 37 10 156 A1 discloses an apparatus for treating infected refuse with the aid of microwaves. The known apparatus includes a microwave chamber into which containers are introduced which are filled with the infected refuse and are hermetically sealed with the aid of a cover. The containers consist of microwave-transmissive material and in the microwave chamber itself a means is provided for moving the containers during the radiation with microwaves. Said means may for example be a conveying belt or a turntable.
The containers themselves may have in their interior a further container for receiving liquid, in particular water.
DE 35 05 571 C2 discloses an apparatus for the disinfection and sterilization of mattresses or the like with the aid of microwaves which comprises a microwave chamber for receiving the mattresses and at least one microwave transmitter for irradiating the moistened mattresses. The essence of this known apparatus resides in that the microwave chamber sealed all round has microwave-transmissive windows through which the microwaves are irradiated into the microwave chamber, that within the microwave chamber a microwave-transmissive mattress chamber is accommodated and that the microwave chamber and mattress chamber communicate with each other, the microwave chamber being formed jointly with the mattress chamber as lock and lock doors being provided on both sides of the mattress chamber.
For the disposal of infectious hospital waste and refuse a number of regulations exist and the observance thereof is supervised by the Federal Ministry of Health, who has also issued a decree in this respect. The basic idea is that in the disposal of infectious hospital refuse no contamination of the environment must occur.
In the microwave treatment of infectious hospital refuse, however, difficulties are encountered in conjunction with the fixedly sealed containers in so far as water must be introduced into the plastic container to permit a heating in the first place of the hospital refuse, which itself is relatively dry. It would for example also be possible to add water in the form of sealed plastic bags which the operator concerned also introduces into the plastic containers after the filling of the latter. However, from the safety point of view such a solution would not be acceptable because it cannot then be ensured that the operator might not occasionally forget to add a water container to the plastic container and that then the heating and sterilization of the hospital refuse would not be possible.
Even in cases where in the containers regions are provided beforehand in which water is kept which is liberated during the microwave treatment so that the refuse in the interior of the container is wetted with water the certainty is still not adequate because the respective operator might just forget to check whether a container used does in fact still contain an undamaged water reservoir.
It must therefore be ensured that irrespective of the attention of the operator the water always reliably enters the containers concerned.
A further problem in heating the infectious hospital refuse in plastic container resides in that the heating causes an excess pressure which might cause the container to burst.